Liver-metastatic breast cancer cells exhibit a unique metabolic program compared to bone or lung metastatic cells, characterized by increased conversion of glucose-derived pyruvate into lactate and decreased mitochondrial metabolism.137 Pyruvate dehydrogenase kinase-1 (PDK1)-dependent metabolic reprogramming is a key regulation of metabolism and liver metastasis in breast cancer. The gene discussed is PDK1; the disease is breast cancer.